Retinoblastoma: A Parent’s Guide to Childhood Eye Cancer
Understanding Retinoblastoma
Retinoblastoma begins in the retina when nerve cells called retinal cells change and grow out of control. These abnormal cells multiply and eventually form a tumor inside the eye. The cancer can affect one eye or both eyes. In rare cases, it may also be associated with a tumor in the brain. This condition is sometimes referred to as trilateral retinoblastoma.
Retinoblastoma represents approximately 6.1% of all cancers in children under five years of age. Roughly 350 new cases are diagnosed each year in the United States (AAO). The incidence is estimated at 11.8 cases per million live births among children in this age group (AAO).
Retinoblastoma is linked to changes in the RB1 gene. This gene normally helps prevent tumors from forming. Every person inherits two copies of the RB1 gene, one from each parent. For retinoblastoma to develop, both copies in a single retinal cell must become damaged or mutated.
In some cases, both mutations happen by chance in a developing retinal cell. In other cases, a child inherits one damaged copy and only needs one additional mutation for a tumor to form. In fewer than 3% of children with retinoblastoma in one eye, the cancer develops even when the RB1 gene is normal. It is instead driven by activity in a different gene called MYCN (AAO).
There are two main forms of retinoblastoma. Hereditary retinoblastoma accounts for about 4 out of 10 cases (American Cancer Society). Children with this form carry a germline mutation in the RB1 gene. This means the mutation is present in every cell of the body. These children often develop tumors in both eyes and tend to be diagnosed at a younger age, with a median onset around 12 months.
Sporadic retinoblastoma makes up about 55% of cases (American Cancer Society). In these children, both RB1 mutations occur only in the retinal cells and are not inherited. Sporadic retinoblastoma typically affects one eye and tends to appear somewhat later in childhood.
Who Is Affected and Risk Factors
Retinoblastoma primarily affects infants and very young children. Most cases are diagnosed before the age of three, and the cancer is uncommon after age five. It affects boys and girls at similar rates and occurs across all racial and ethnic groups.
The most important risk factor for retinoblastoma is a family history of the disease. If a parent had retinoblastoma as a child, there is a 50% chance of passing the RB1 gene mutation to each of their children (AAO). About 60% of children who inherit the gene will develop tumors in both eyes. Another 30% will develop a tumor in one eye. The remaining 10% may carry the gene but not develop retinal tumors (AAO).
Genetic testing can help families understand their risk. If there is any family history of retinoblastoma, parents should discuss genetic counseling and testing with their child's doctor as early as possible.
Children with hereditary retinoblastoma face an increased lifetime risk of developing other types of cancer. These include sarcomas of bone and soft tissue, melanoma (a type of skin cancer), and cancers of the brain, breast, and lung. Long-term follow-up and cancer surveillance are important for these individuals throughout their lives.
Signs and Symptoms
The most common and recognizable sign of retinoblastoma is leukocoria. This is a white or pale appearance of the pupil. In a healthy eye, the pupil appears dark or may look red when a camera flash is used. In a child with retinoblastoma, the affected pupil may appear white or cloudy. This is especially noticeable in flash photographs or when light shines into the eye.
Parents often first notice this sign in photographs of their child. Any white reflection or glow in a child's pupil should be reported to a doctor right away.
Strabismus, or eyes that appear to look in different directions, can be another sign of retinoblastoma. While strabismus has many possible causes, it can indicate that a tumor is affecting vision in one eye. This may cause that eye to drift.
Additional symptoms may include the following:
- Redness or swelling of the eye
- A pupil that appears larger than usual or does not respond normally to light
- Poor vision or a change in the appearance of the eye
- Pain in or around the eye, though this is less common in early stages
If a child shows any of these symptoms, parents should seek an eye examination promptly. Early detection significantly improves treatment outcomes.
Diagnosis and Testing
A retina specialist or ocular oncologist diagnoses retinoblastoma primarily by examining the inside of the eye. The doctor uses specialized instruments to look through the pupil and view the retina directly. A traditional biopsy (removing a tissue sample) cannot be performed safely. Doing so risks the spread of cancer cells.
Examinations in young children are typically done under general anesthesia. This allows the doctor to thoroughly examine the entire retina of both eyes.
Magnetic resonance imaging (MRI) is the preferred imaging tool for evaluating retinoblastoma. An MRI can show the size and location of tumors inside the eye. It can also determine whether the cancer has spread beyond the eye. B-scan ultrasonography (a type of ultrasound for the eye) may also be used to help measure tumors and monitor changes over time.
Genetic testing of a blood sample can determine whether a child carries a germline RB1 mutation. This information helps doctors understand whether the retinoblastoma is hereditary. It also guides recommendations for monitoring siblings and future children.
A newer approach involves a liquid biopsy of the aqueous humor (the clear fluid in the front of the eye). This clinically validated test, available since 2017, allows doctors to confirm the diagnosis. It also identifies molecular features of the tumor without a traditional biopsy. This can help guide treatment decisions and provide information about the expected course of the disease.
Treatment Options
Chemotherapy is the most common treatment for retinoblastoma and is often the first approach. The goal of chemotherapy is to shrink the tumor and may help a child avoid surgery. There are several ways chemotherapy can be delivered.
- Intravenous chemotherapy: Cancer-fighting drugs are given through a vein and travel throughout the body to reach the tumor.
- Intra-arterial chemotherapy: A specialist threads a thin tube through an artery to the blood vessel supplying the eye. The medication is delivered directly, allowing a high drug concentration at the tumor.
- Intravitreal chemotherapy: Medication is injected directly into the vitreous (the gel inside the eye) to target tumors that have seeded into the vitreous cavity.
Radiation therapy uses high-energy beams to destroy cancer cells. Internal radiation therapy, also called plaque brachytherapy, involves placing a small disc-shaped device behind the eye near the tumor. This device delivers targeted radiation over several days. The implant is temporary and is usually removed after about seven days.
External beam radiation therapy directs radiation from outside the body. It is used less often today because of potential long-term side effects. These include an increased risk of secondary cancers in children with hereditary retinoblastoma.
For smaller tumors, doctors may use focal treatments. Laser photocoagulation (thermal laser treatment) uses heat from a focused light beam to destroy blood vessels that feed the tumor. Cryotherapy (freezing treatment) applies extreme cold to destroy cancer cells. These treatments are sometimes used after chemotherapy has reduced the tumor size.
If the tumor is very large or if other treatments have not controlled the cancer, surgical removal of the eye (enucleation) may be necessary. While this is a difficult decision for families, enucleation can be life-saving when the cancer threatens a child's life. After surgery, an artificial eye (prosthesis) can be fitted that closely matches the other eye.
Researchers are exploring new treatment approaches for retinoblastoma. One area of active study involves immunotherapy, which uses the body's own immune system to fight cancer. Research published in Nature Cancer (2020) found that a combination of immune system T-cells and an immune-boosting drug preserved vision in laboratory models. While this research is still in early stages, it represents a promising direction for future treatment.
What to Expect
The treatment plan for retinoblastoma depends on several factors. These include the size and location of the tumor, whether one or both eyes are affected, and whether the cancer has spread. Treatment often involves a team of specialists, including a retina specialist, ocular oncologist, pediatric oncologist, and radiation oncologist.
Many children require multiple rounds of treatment. Chemotherapy may be followed by focal treatments such as laser or cryotherapy to eliminate remaining tumor cells. Regular eye examinations under anesthesia are needed throughout treatment and for years afterward to watch for recurrence.
The outlook for children with retinoblastoma in the United States is very good. More than 9 out of 10 children with retinoblastoma are successfully treated (American Cancer Society). However, retinoblastoma that has spread outside the eye can be more difficult to treat. This underscores the importance of early diagnosis.
Vision outcomes depend on the size and location of the tumor. Some children retain good vision, while others may experience partial or complete vision loss in the affected eye. The primary goal of treatment is to save the child's life. Preserving the eye and vision are secondary but important objectives.
Living with Retinoblastoma
Children treated for retinoblastoma need ongoing monitoring. Frequent eye examinations continue for several years after treatment to check for recurrence. Children with hereditary retinoblastoma require lifelong cancer surveillance. This is because of their elevated risk of developing other cancers later in life.
A retina specialist or ocular oncologist will create a follow-up schedule tailored to each child's needs. Parents should keep all recommended appointments and report any changes in their child's eyes or vision promptly.
If a child loses vision in one eye, early intervention services and vision therapy can support normal development. Many children adapt well to having vision in only one eye. Schools and pediatricians can help identify resources to support learning and daily activities.
Children who retain vision in both eyes may still need corrective lenses or other support. This depends on the effects of treatment on their eyes.
Families affected by retinoblastoma should consider genetic counseling. Understanding whether the hereditary form is present helps guide decisions about screening siblings and monitoring future children. If a parent carries the RB1 mutation, each child has a 50% chance of inheriting it (AAO). Early and frequent screening of at-risk children can catch tumors when they are small and easier to treat.
When to See a Retina Specialist
Parents should seek immediate medical attention if they notice a white glow or reflection in their child's pupil, especially in photographs. A white pupil is not normal and should be evaluated right away. Other reasons to seek prompt care include misaligned eyes, unexplained redness or swelling, or any sudden change in a child's vision or eye appearance.
Children with a family history of retinoblastoma should begin eye examinations shortly after birth. A retina specialist or ocular oncologist can perform dilated eye exams to look for early signs of tumors. For children known to carry the RB1 mutation, frequent examinations throughout early childhood are essential.
If there is any family history of retinoblastoma, parents should inform their child's pediatrician. A referral to a specialist experienced in diagnosing and treating this condition should be requested.
Questions and Answers
Yes. In families with a known history of retinoblastoma, genetic testing can identify at-risk children before any tumor develops. These children can then be closely monitored with frequent eye examinations beginning at birth. Early detection through screening often finds tumors when they are small and more treatable. This can improve both survival and vision outcomes.
Not in every case. Many children are successfully treated with chemotherapy, laser therapy, cryotherapy, or radiation without needing surgery. Enucleation (surgical removal of the eye) is typically reserved for large tumors that have not responded to other treatments. It may also be needed if the tumor poses a risk to the child's life. A retina specialist or ocular oncologist will discuss all available options with the family.
Yes. Siblings of a child with retinoblastoma should be evaluated, especially if the affected child has the hereditary form. Genetic testing can determine whether siblings carry the RB1 mutation. Even if genetic testing is not immediately available, siblings should receive a comprehensive eye examination from a retina specialist or ocular oncologist.
The survival rate for retinoblastoma in the United States is very high. More than 9 out of 10 children are successfully treated (American Cancer Society). Children with the hereditary form do face an increased lifetime risk of developing other cancers. Ongoing health monitoring is important. Many retinoblastoma survivors lead full, healthy lives with appropriate follow-up care.
Retinoblastoma can recur, which is why regular follow-up examinations are critical. Recurrence is most common in the first few years after treatment. If a tumor does return, additional treatment options are available. Children with hereditary retinoblastoma also have a risk of developing new tumors in the same or opposite eye. Ongoing surveillance is especially important throughout early childhood.